The present invention relates generally to Multiple Integrated Laser Engagement System (MILES) type training devices, and more particularly to an acoustic training device for simulating the effects of unexploded submunitions in a tactical engagement simulation system such as the MILES.
"Submunition" are weapons that are delivered en masse by being packaged in containers that comprise a weapon system. For example: cluster bombs contain many small bomblets (submunitions) which are clustered together and delivered simultaneously. Once dispersed a submunition becomes an individual, independent, and lethal weapon system. Similarly, a dispersed submunition simulator becomes an independent weapon simulator.
The MILES has revolutionized the way in which armies train for combat. MILES has been fielded with armies of many nations around the world and has become the international standard against which all other Tactical Engagement Simulation (TES) systems are measured. For the U.S. Army and Marine Corps, MILES is the keystone of their opposing force, free-play TES program. It is highly valued in its ability to accurately assess battle outcomes and to teach soldiers the skills required to survive in combat and destroy the enemy. With MILES, commanders at all levels can conduct opposing force free-play tactical engagement simulation training exercises which duplicate the lethality and stress of actual combat.
The MILES system uses laser "bullets" to simulate realistically the lethality of a modern battlefield. Eye-safe Gallium Arsenide (GaAs) laser transmitters, capable of shooting pulses of coded infrared energy, simulate the effects of live ammunition. The transmitters are easily attached to and removed from all hand-carried and vehicle-mounted direct-fire weapons. Detectors located on opposing troops and vehicles receive coded laser pulses. MILES decoders then determine whether the target was hit by a weapon which could cause damage (hierarchy of weapons effects) and whether the laser bullet was accurate enough to cause a casualty. The target vehicle or troops are made instantly aware of the accuracy of the shot by means of audio alarms and visual displays, which can indicate either a hit or a near miss.
The codeed infrared energy is received by silicon detectors located on the target. In the case of ground troops, the detectors are installed on webbing material which resembles the standard-issue load-carrying lift harness. Additional detectors are attached to a web band which fits on standard-issue helmets. For vehicles, the detectors are mounted on belts which easily attach to the front, rear, and sides. The detectors provide 360.degree. azimuthal coverage and sufficient elevation coverage to receive the infrared energy during an air attack. The arriving pulses are sensed by detectors, amplified, and then compared to a threshold level. If the pulses exceed the threshold, a single bit is registered in the detection logic. Once a proper arrangement of bits exists, corresponding to a valid code for a particular weapon, the decoder decides whether the code is a near miss or a hit. If a hit is registered, a hierarchy decision is made to determine if this type of weapon can cause a kill against this type of target and, if so, what the probability of the "kill" might be.
While great success has been enjoyed with weapons that can be aimed, there has been no convenient or economic way for the military to incorporate grenades, mines, submunitions and other omnidirectional weaponry into their tactical exercises using the MILES. Grenades, for instance, tend to rotate during flight and would require a plurality of laser emitters to simulate a burst. Even were it economical to provide several laser emitters on each grenade, there is still the possibility that a player may be obstructed from view and thus unrealistically protected. Similarly, unexploded submunitions may be laying in tall grass or under a rock when disturbed, effectively attenuating any possible visual signal.
Copending patent application Ser. No. 07/691,603, entitled "Apparatus and Method for Interfacing Indirect-Fire Devices with MILES," uses a predetermined acoustic signal to simulate an explosion in combination with receiver circuitry sensitive to the acoustic signal and operatively connected to the existing MILES power supply. A special feature presently incorporated in the MILES provides for an audible alarm to be activated upon removal and reinsertion of the MILES power source. This feature prevents someone from cheating by deactivating his MILES receiver during simulated combat. When the power source (typically a battery) is reinstalled an audible alarm is sounded. Consequently, by momentarily removing the MILES power source from the circuit for a brief instant and then reconnecting it back into the circuit the interfacing device is able to indicate a "kill" on MILES. This operation is performed when receiver circuitry detects a predetermined acoustic signal of sufficient amplitude and duration or can even be a coded acoustic signal. An acoustic signal overcomes the disadvantages of highly directional laser pulses because of its substantially omnidirectional propagation characteristics.
Training devices which generate a predetermined acoustic signal of sufficient amplitude and duration and/or coded acoustic signals are described in copending patent application Ser. No. 07/983,952, entitled "Acoustic Training Device for Use in a Tactical Engagement System." Particular training devices which simulate a grenade, a "Bouncing Betty," and a Claymore mine are also described in copending patent applications Ser. Nos. 07/608,923, 07/708,253 and 08/002,367, respectively. All of these training devices are designed to accurately simulate the effects of a properly functioning weapon in a tactical engagement simulation.
The present invention, on the other hand, is intended to simulate the effects of a weapon which has failed to operate after deployment. Many of the submunitions and M42/M46-type grenades now in use require a mechanical firing pin to impact a stab detonator in order to initiate the explosives found in these devices. It has been demonstrated that a firing system relying on a firing pin to strike a stab detonator is not sensitive to impact angles significantly less than 90.degree. with respect to the target. Consequently, the battlefield can become littered with armed submunitions that can then be triggered upon contact by vehicles or personnel walking through the battlefield.
An example of such a mechanical submunition firing system is exhibited in the Army M223 fuze, which is employed in M42/M46 submunition grenades. These grenades, described in U.S. Pat. No. 4,852,496, to Campagnuolo, are stacked atop one another and are delivered either by artillery projectile or rocket cargo rounds.
In addition to the M42/M46 grenades, there exists a host of other submunitions used by the Navy, Air Force and Marines. Some of these include the M118 Rockeye submunition grenade which is launched by aircraft, and the blue series of submunition grenade which are spherical bomblets also delivered by aircraft.
If any of these submunition grenades do not function after release, either from aircraft, bomb, rocket or artillery projectile, they will lie upon the ground and remain live. Any disturbance will then cause them to explode. The disturbance can occur whenever a vehicle drives over the submunition, or even when a soldier or civilian picks one up out of curiosity or in an attempt to recover souvenirs. This can be particularly troublesome in a desert environment where the relatively soft impact afforded by the sand results in a significant number of "duds."